This is an acid-base reaction (neutralization): Na2SO3 is a base, H2SO4 is an acid.
Reactants:
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Na2SO3 – Sodium sulfite
Other names: Sodium sulphite, Hypo clear (photography), E221
Appearance: White solid ; White crystals or powder
H2SO4 – Sulfuric acid
Other names: Oil of vitriol, Sulfuric acid, concentrated (> 51% and , H2SO4
Appearance: Clear, colorless liquid ; Odourless colourless oily hygroscopic liquid ; Colorless to dark-brown, oily, odorless liquid. [Note: Pure compound is a solid below 51°F. Often used in an aqueous solution.]
Products:
SO2 – Sulfur dioxide
Other names: Sulfurous anhydride, Sulphur dioxide, Sulfurous acid anhydride
Appearance: Colorless gas ; Colourless gas or compressed liquefied gas with pungent odour ; Colorless gas with a characteristic, irritating, pungent odor. [Note: A liquid below 14°F. Shipped as a liquefied compressed gas.]
Na2SO4
Names: Sodium sulfate, Sodium sulphate, Sulfate of sodium
Appearance: White crystalline solid | hygroscopic ; White hygroscopic solid in various forms
H2O – Water, oxidane
Other names: Water (H2O), Hydrogen hydroxide (HH or HOH), Hydrogen oxide
Appearance: White crystalline solid, almost colorless liquid with a hint of blue, colorless gas
